DIY an FM Radio Dipole Antenna | FMUSER BROADCAST
The FM dipole antenna is the simplest and most extensive type of antenna, so it's easy for anyone to make their own one, which only needs some simple materials. a DIY FM dipole antenna is a practical and low-cost choice if your radio needs a temporary antenna. So how to DIY an FM dipole antenna? The article wil tell you.
What Is An FM Dipole Antenna?
It is important to have a brief understanding of FM dipole antenna before setting about making your own one. In the field of radio and telecommunications, the FM dipole antenna is the most widely used and simplest type of antenna. It has obvious features: it looks like the word "T", which is composed of two conductors with equal length and end-to-end. Their feet are connected with the cable. The cable can be an open cable, double cable, or coaxial cable.
It should be noted that balun should be used when using a coaxial cable because the coaxial cable is a kind of unbalanced cable but the FM dipole antenna is a kind of balanced antenna. And balun can make them be matched with each other.
You need to prepare some materials for making an FM dipole antenna as well. They are generally:
- Twin flex - Twin mains flex is ideal, but you can replace it with other wires, such as old speaker wires, as long as their resistance is close to 75 ohms.
- Tie wrap - It is used to secure the center of the FM dipole antenna and prevent the flex from opening out beyond what is needed.
- String or twine - It is used to secure the ends of the FM dipole antenna to a certain point (if required).
- Connectors - It is used for connecting the FM antenna to a coaxial cable.
These materials can be found in your daily life. You can even use those found in the waste pile to make the VHF FM radio dipole antenna.
Then it's needed to calculate the length of your VHF FM dipole antenna. You can calculate according to this formula:
L=468/F : L refers to the length of the antenna, so the length of the conductor needs to be divided by 2. F is the working frequency in MHz. When these above are ready, you can start making antennas.
It is easy to make an ordinary VHF FM dipole antenna, which only needs 4 simple steps. Follow the guidance below!
- Separate the cable - Separate the two insulated wires of the cable.
- Fix the center point - Remember your conductor length? Let's assume that it's 75 centimeters. When the conductor is 75 cm long enough, stops separating the wires. Then tie the middle with tie wrap at this time. And this is the center of the FM dipole antenna.
- Adjust the length of the conductor - Then you can adjust the length of the conductor slightly. Because there are many factors affecting the constant in the conductor length formula, it is impossible to be accurate at any time. If you need a higher operating frequency, you can shorten the conductor length slightly.
- Fix the antenna - Finally, tie a knot at the end of the wire so that you can fix the antenna with some twisted wires. When installing the FM dipole antenna, pay attention to stay away from metal objects, or the signal reception quality will be reduced.
The VHF FM receiver can be used for a 75-ohm interface and 300-ohm interface. The above FM dipole antenna is suitable for the 75-ohm interface. If you want to use a 300-ohm interface, you can try two methods:
- Connect your DIY 75-ohm dipole antenna with a coaxial cable with a balun
- Buy 300 ohm FM cable online and make a 300-ohm dipole antenna in the same way as making a 75-ohm dipole antenna.
It is noted that it is only recommended to use the DIY FM dipole antenna for your radio or audio receiver. If you need an antenna for the FM radio transmitter, please buy a professional FM dipole antenna from a professional radio equipment provider, such as FMUSER.
What Is A Balun For A Dipole ?
Baron's principle is similar to that of a transformer. A balun is an electrical device that converts between a balanced signal and an unbalanced signal, or feed line.
When Should I Use An Antenna Balun?
Balances are used in many areas to transition between balanced & Unbalanced scenarios: one key area is for radio frequency, RF applications for antennas. RF balances are used with many antennas and their feeders to transform a balanced feed or line to an unbalanced one, Since the dipole antenna is a balanced antenna and the coaxial cable is an unbalanced cable, the coaxial cable needs to use balun to change the coaxial cable into a balanced cable.
What Are The Different Types of FM Dipole Antennas ?
There are four main types of FM dipole antennas:
- Half-wave dipole antenna
- Multi half-wave dipole antenna
- Folded dipole antenna
- short dipole
What kind of Feeder Is The Best FM Dipole Antenna ? Which Feeding Method Is Best ?
The dipole antenna is a balanced antenna, so you should use a balanced feeder, which is true in theory. However, a balanced feeder is rarely used because it is difficult to operate in buildings and is only applicable to the HF band. More coaxial cables with balun are used.
The FM dipole antenna is widely used in various radio broadcasting scenarios, like personal FM radio because of its simplicity, efficiency, and low cost. But if you need to build a radio station, finding a reliable radio equipment supplier is still your best choice. FMSUER is such a professional and reliable supplier of radio broadcasting equipment and solutions, including practical and low-cost FM radio transmitters for sale, matched FM dipole antennas for sale, and so on. If you are looking for these, please feel free to contact us!
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